Make It Legal, I'm hoping your girlfriend will be as helpful as Hilder, but if she's not, just give yourself more time and less pressure. As you're getting into what's going on, concentrate on the physical feelings and the pleasure instead of the procedural aspects. It's focusing on the steps themselves that causes you to lose your concentration on the sensations. That'll take the wind out of anyone's sails. In other words, just close your eyes and go with the physical sensations. Let the animal instinct take over and not your conscious or self-conscious mind.